The immediate early gene c-fos is one of the most studied genes in the CNS as a marker for neuronal activation (Edwards et al.,1999; Abraham and Kovacs,2000; Konkle and Bielajew,2004). It is thus generally believed that activation of a neuronal system with c-fos expression in the brain is a hallmark for reflecting the functional status of a discrete brain structure. The c-fos belongs to the family of immediate-early transcription factor genes that are believed to function in coupling short-term signals elicited by extracellular to long-term changes in cellular phenotype by orchestrating changes in target gene expression (Curran and Morgan,1995). However, the expression of c-Fos, which is normally low, can be increased by a number of pharmacological, physiological, and behavioral manipulations (Morgan and Curran,1989; Herrera and Robertson,1996). Therefore, the measurement of c-Fos protein levels, the product of ...

We examined the effects of selective agonists of ionotropic excitatory amino acid (EAA) receptor subtypes on induction of the immediate early gene c-fos. We used in situ hybridization to measure c-fos mRNA and fura-2 imaging to measure intracellular calcium (Ca2+i) in individual dentate gyrus neurons maintained in vitro. Activation of either NMDA or non-NMDA receptor subtypes is sufficient to induce the rapid and dramatic increase of c-fos mRNA. Activation of either NMDA or non-NMDA receptors also induces a rapid and dramatic increase of Ca2+i, effects blocked by the removal or chelation of extracellular calcium (Ca2+e). c- fos mRNA induction by either receptor subtype is Ca2+ dependent, since chelation of Ca2+e with EGTA prevents c-fos mRNA induction by both NMDA and non-NMDA receptor agonists. The increase in Ca2+i induced by activating non-NMDA receptors is inhibited either by removal of extracellular sodium (Na+e) or by ...

This thesis examines mechanisms of regulation of neuropeptide gene expression in vivo in some neurosecretory hypothalamic neurones of the rat. In particular, the influence of neural pathways, acting via receptors and subsequent regulation of genetic transcription factors was measured and second messenger pathways were directly manipulated and the effects of their mutation on gene expression were measured. The magnocellular neurones of the supraoptic nucleus (SON) are known to be directly (i.e. non-synaptically) osmosensitive. Fos, the protein product of the immediate early gene c-fos, has been used as a marker of neuronal activation and its expression is induced in these neurones by increasing systemic hyperosmolarity. The effects of acute, direct hyperosmotic stimulation, via a microdialysis probe, on Fos expression in supraoptic nucleus magnocellular neurones was investigated. Fos expression was detected by immunohistochemistry (IHC). ...

Many studies on memory and learning utilize the immediate early gene c-Fos as an indicator of recent synaptic activity. By quantifying c-Fos positive neurons, we can compare activity across different populations in the brain, and analyze co-labelled neurons with other useful cell markers such as BrdU and Doublecortin. Our lab…. read more. ...

BACKGROUND: Pancreatic polypeptide (PP) is a potent anti-obesity agent known to inhibit food intake in the absence of nausea, but the mechanism behind this process is unknown. METHODOLOGY/PRINCIPAL FINDINGS: Here we demonstrate that in response to i.p. injection of PP in wild type but not in Y4 receptor knockout mice, immunostaining for the neuronal activation marker c-Fos is induced specifically in neurons of the nucleus tractus solitarius and the area postrema in the brainstem, notably in cells also showing immunostaining for tyrosine hydroxylase. Importantly, strong c-Fos activation is also detected in the arcuate nucleus of the hypothalamus (ARC), particularly in neurons that co-express alpha melanocyte stimulating hormone (alpha-MSH), the anorexigenic product of the proopiomelanocortin (POMC) gene. Interestingly, other hypothalamic regions such as the paraventricular nucleus, the ventromedial nucleus and the lateral hypothalamic area also show c-Fos ...

We have generated transgenic mice expressing the proto-oncogene c-fos from an H-2Kb class I MHC promoter as a tool to identify and isolate cell populations which are sensitive to altered levels of Fos protein. All homozygous H2-c-fosLTR mice develop osteosarcomas with a short latency period. This phenotype is specific for c-fos as transgenic mice expressing the fos- and jun-related genes, fosB and c-jun, from the same regulatory elements do not develop any pathology despite high expression in bone tissues. The c-fos transgene is not expressed during embryogenesis but is expressed after birth in bone tissues before the onset of tumor formation, specifically in putative preosteoblasts, bone-forming osteoblasts, osteocytes, as well as in osteoblastic cells present within the tumors. Primary and clonal cell lines established from ...

The expression of the immediate early gene product c-Fos is a reliable molecular marker to investigate neuronal activation. The examination of c-Fos expression has revealed that many brain regions are activated by MS, which differs depending on age and the type of stress. We recently analyzed the c-Fos expression induced by repeated MS and single-time MS during different developmental stages and time periods. Mice were exposed to 3 h repeated MS daily from PND1 to PND14 or from PND14 to PND21, or to single-time MS at PND14 or PND21 (Horii-Hayashi et al., 2013). We clarified that MS activated many brain regions and that c-Fos expression patterns changed developmentally (Figure 2). Single-time MS at both ages activated many regions of the hypothalamus and limbic forebrain, while the pattern of c-Fos expression in the repeated MS groups were significantly different on PND14 and PND21. In repeated MS of PND14 mice, the ...

In order to elucidate the role of the vestibulocerebellar neural circuits during two-stage bilateral labyrinthectomy (BL) we examined Fos-like immunoreactive (-LIR) neurons as a marker of neural activation in the rat brainstem after BL and the projec

Oncogenic activation of Abl proteins due to structural modifications can occur as a result of viral transduction or chromosomal translocation. The tyrosine protein kinase activity of oncogenic Abl proteins is known to be essential for their transforming activity. Therefore, we have attempted to identify selective inhibitors of the Abl tyrosine protein kinase. Herein we describe an inhibitor (CGP 57148) of the Abl and platelet-derived growth factor (PDGF) receptor protein-tyrosine kinases from the 2-phenylaminopyrimidine class, which is highly active in vitro and in vivo. Submicromolar concentrations of the compound inhibited both v-Abl and PDGF receptor autophosphorylation and PDGF-induced c-fos mRNA expression selectively in intact cells. In contrast, ligand-induced growth factor receptor autophosphorylation in response to epidermal growth factor (EGF), insulin-like growth factor-I, and insulin showed no or weak inhibition by high ...

The inhibition of GLUT2-mediated sugar detection increased food intake in GLUT2-SDD mice (line TgG) by enlarging meal sizes without changes in meal frequency. The decision to stop eating is delayed in conjunction with defects in arcuate c-Fos activation in response to glucose and changes in orexin and TRH neuropeptide mRNA levels in the hypothalamus of fed mice. Thus, GLUT2 receptor function, independent of sugar transport and metabolism, is involved in controlling feeding behavior.. GLUT2 plays a key role in glucodetection, which controls the feeding behavior in mice. Indeed, daily food intake is similarly increased in GLUT2-SDD (line TgG) and in GLUT2-null rescued (ripglut1;glut2−/−) mice (5), and in both mouse models, provision of glucose failed to reduce food intake. GLUT2-dependent sugar transport (except in pancreatic β-cells) and sugar detection were invalidated in GLUT2-null mice; by contrast, GLUT2-SDD mice lack only the receptor function, and thus sugar transport was still able to ...

Expression of cellular oncogenes was studied in a T cell hybridoma that undergoes cytolytic activation when stimulated by specific antigen or by anti-Thy-1 antibody. The activation occurs without induction of hybridoma proliferation, providing a model to examine oncogene expression during functional differentiation of lymphocytes. We found that c-fos and c-ets-1 mRNAs were transiently induced at high levels in the hybridoma 30 min and 4 h after stimulation, respectively. c-myc and c-ets-2 oncogenes were constitutively expressed in the hybridoma and their mRNA levels were unaffected during 4 h of stimulation, although c-myc expression was reduced in the later stage of stimulation. Inhibitors of T cell activation, cyclosporin A and anti-LFA-1 antibody, blocked the induction of c-fos and c-ets-1 mRNAs without reducing the levels of c-myc and c-ets-2. The results indicate that ...

Functionally, parallel circuits from NAc-S and NAc-C have been shown previously to mediate different aspects of the way Pavlovian conditioning influences instrumental actions with the NAc-S mediating specific PIT and the NAc-C general PIT, a form of PIT associated with general motivational arousal as opposed to the highly selective predictions of specific outcomes (Hall et al., 2001; Corbit and Balleine, 2011). Both regions of the accumbens also receive inputs from the basolateral amygdala (BLA) that affect instrumental action and yet it is the BLA to NAc-S pathway that controls specific PIT (Shiflett and Balleine, 2010). From a functional perspective, therefore, is not surprising that signals from distinct regions of nucleus accumbens, project to separate regions in the VP and that, in the current study, we found that a significant proportion of c-Fos-positive neurons in the NAc-S projected to the VP-m. Indeed, a single axon tracing study of NAc-S neurons found that all short- and ...

Orexins are novel appetite-stimulating peptides expressed in the lateral hypothalamic area (LHA), and their expression is stimulated by hypoglycemia in fasted rats. We investigated activation of orexin and other neurons during insulin-induced hypoglycemia using the immediate early gene product Fos. Insulin (50 U/kg) lowered plasma glucose by ,50% after 5 h and stimulated feeding sixfold compared with saline-injected controls. Hypoglycemic rats allowed to feed and normoglycemic controls both showed sparse Fos-positive (Fos+) neurons in the LHA and the paraventricular nucleus (PVN) and arcuate nucleus (ARC) and showed none in the nucleus of the solitary tract (NTS), which relays visceral feeding signals to the LHA. In the LHA, total numbers of Fos+ neurons were comparable in fed hypoglycemic and control groups (60 ± 6 vs. 52 ± 4 cells/mm2, P , 0.05), as were Fos+ neurons immunoreactive for orexin (1.4 ± 0.4 vs. 0.6 ± 0.4 ...

We report here that levels of c-fos mRNA in GnRH neurons are elevated significantly coincident with the first increase in LH levels at the time of an E- and P-induced LH surge in female rats. Similarly, Fos protein increases in GnRH neurons near the time of the LH surge in rats (Lee et al., 1990a; Hrabovszky et al., 1995; Wang et al., 1995), mice (Wu et al., 1992), hamsters (Berriman et al., 1992;Doan and Urbanski, 1994), and sheep (Moenter et al., 1993). In rats, Fos protein is first detectable in GnRH neurons after the onset of the expected LH surge, and the number of GnRH neurons expressing Fos increases during the ascending phase of the LH surge (Lee et al., 1990a, 1992b). These results agree with those of the present study showing that c-fos gene expression increases in GnRH neurons near the onset of the LH surge. Synaptic blockade with phenobarbital or MK-801 (an NMDA channel blocker) inhibits the LH surge and the ...

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It is unknown how the brain coordinates decisions to withstand personal costs in order to prevent other individuals' distress. Here we test whether local field potential (LFP) oscillations between brain regions create "neural contexts" that select specific brain functions and encode the outcomes of these types of intersubjective decisions.Rats participated in an "Intersubjective Avoidance Test" (IAT) that tested rats' willingness to enter an innately aversive chamber to prevent another rat from getting shocked. c-Fos immunoreactivity was used to screen for brain regions involved in IAT performance. Multi-site local field potential (LFP) recordings were collected simultaneously and bilaterally from five brain regions implicated in the c-Fos studies while rats made decisions in the IAT. Local field potential recordings were analyzed using an elastic net penalized regression framework.Rats voluntarily entered an innately aversive chamber to prevent another rat from getting ...